Department of Applied Physics, The Rachel and Selim Benin School of Engineering and Computer Science, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel.
Department of Applied Physics, The Rachel and Selim Benin School of Engineering and Computer Science, The Hebrew University of Jerusalem, Edmond J. Safra Campus, Jerusalem 91904, Israel; Department of Physics, Ariel University, Ariel 40700, Israel.
Environ Res. 2018 May;163:208-216. doi: 10.1016/j.envres.2018.01.032. Epub 2018 Feb 22.
In the interaction of microwave radiation and human beings, the skin is traditionally considered as just an absorbing sponge stratum filled with water. In previous works, we showed that this view is flawed when we demonstrated that the coiled portion of the sweat duct in upper skin layer is regarded as a helical antenna in the sub-THz band. Experimentally we showed that the reflectance of the human skin in the sub-THz region depends on the intensity of perspiration, i.e. sweat duct's conductivity, and correlates with levels of human stress (physical, mental and emotional). Later on, we detected circular dichroism in the reflectance from the skin, a signature of the axial mode of a helical antenna. The full ramifications of what these findings represent in the human condition are still unclear. We also revealed correlation of electrocardiography (ECG) parameters to the sub-THz reflection coefficient of human skin. In a recent work, we developed a unique simulation tool of human skin, taking into account the skin multi-layer structure together with the helical segment of the sweat duct embedded in it. The presence of the sweat duct led to a high specific absorption rate (SAR) of the skin in extremely high frequency band. In this paper, we summarize the physical evidence for this phenomenon and consider its implication for the future exploitation of the electromagnetic spectrum by wireless communication. Starting from July 2016 the US Federal Communications Commission (FCC) has adopted new rules for wireless broadband operations above 24 GHz (5 G). This trend of exploitation is predicted to expand to higher frequencies in the sub-THz region. One must consider the implications of human immersion in the electromagnetic noise, caused by devices working at the very same frequencies as those, to which the sweat duct (as a helical antenna) is most attuned. We are raising a warning flag against the unrestricted use of sub-THz technologies for communication, before the possible consequences for public health are explored.
在微波辐射与人类的相互作用中，传统上认为皮肤仅仅是一个充满水的吸收海绵层。在之前的工作中，我们表明这种观点是有缺陷的，因为我们证明了在上皮层的汗腺的螺旋部分在亚太赫兹波段被视为螺旋天线。实验表明，人体皮肤在亚太赫兹区域的反射率取决于出汗强度，即汗腺的电导率，并与人体压力（身体、精神和情绪）水平相关。后来，我们在皮肤的反射率中检测到圆二色性，这是螺旋天线轴模的特征。这些发现对人类状况的全部影响仍不清楚。我们还发现心电图（ECG）参数与人体皮肤的亚太赫兹反射系数相关。在最近的一项工作中，我们开发了一种独特的人体皮肤模拟工具，考虑到皮肤的多层结构以及嵌入其中的汗腺的螺旋段。汗腺的存在导致皮肤在极高频率带中的比吸收率（SAR）非常高。本文总结了这一现象的物理证据，并考虑了其对未来无线通信中电磁频谱利用的影响。自 2016 年 7 月起，美国联邦通信委员会（FCC）为 24GHz 以上的无线宽带操作（5G）采用了新规则。预计这种向亚太赫兹区域更高频率的开发趋势将会扩大。人们必须考虑到设备在与汗腺（作为螺旋天线）最匹配的频率上工作所产生的电磁噪声对人体的影响。在探索亚太赫兹技术对公共健康的可能影响之前，我们呼吁对该技术的使用进行限制。
